VIN (Chassis Number) Generator

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VIN check digit

VIN check digit: how position 9 is calculated

Of a VIN's 17 positions, the 9th is the only one that comes from a calculation: a modulo-11 check applied over the other 16 positions, using a fixed table to turn letters into numbers.

Transliteration, weights and the remainder of dividing by 11

Each VIN character becomes a number before entering the calculation: digits keep their own value, and letters follow a fixed ISO 3779 table, A=1, B=2, C=3, D=4, E=5, F=6, G=7, H=8, J=1, K=2, L=3, M=4, N=5, P=7, R=9, S=2, T=3, U=4, V=5, W=6, X=7, Y=8, Z=9 (I, O and Q do not exist in a VIN). Each of the 17 positions has a weight: 8, 7, 6, 5, 4, 3, 2, 10, 0, 9, 8, 7, 6, 5, 4, 3, 2, with position 9 itself having weight 0 (it does not enter its own sum).
Multiply each value by its position's weight, sum everything, and take the remainder of dividing by 11. The check digit is that remainder, except when the remainder is 10, in which case the digit becomes the letter X. The reference VIN 1M8GDM9AXKP042788 confirms the calculation: the weighted sum of the other 16 positions is 351, whose remainder when divided by 11 is 10, which is why position 9 is X.

Verified example

Reference VIN (digit X)

Input: 1M8GDM9AXKP042788
Expected output: dígito verificador X confere

Weighted sum = 351; 351 mod 11 = 10; a remainder of 10 becomes X.

Same VIN with a tampered digit

Input: 1M8GDM9A0KP042788
Expected output: inválido, esperado X

Changing only position 9 (from X to 0) already breaks validation, the rest of the calculation stays the same.

Full tool FAQ

Is the generated VIN from a real vehicle?

No. It is a synthetic 17-character sequence computed only to satisfy the ISO 3779 check digit. The tool never queries a manufacturer, NHTSA or DENATRAN.

Why does a VIN never contain the letters I, O or Q?

How does the position-9 check digit work?

Does Brazil use the same VIN standard as the United States?

What do positions 12 to 17 mean?

Can I use the generated VIN to sell or list a vehicle?

Does a VIN with a correct check digit guarantee the vehicle has no liens?

Does the tool send the VIN to a server?

Frequently asked questions

Why does a remainder of 10 become the letter X instead of the number 10?

Because the check digit must fit a single VIN position. Since possible remainders range from 0 to 10, and 10 is not a single digit, ISO 3779 uses the letter X to represent that specific case.

Why does position 9 have weight 0 in the table?

Because it is the result of the calculation itself, not an input. Giving it weight 0 ensures whatever value already sits there (or a placeholder, when generating a new VIN) does not interfere with the sum that computes it.

Is this the same calculation used in the US?

Yes, it is the same international ISO 3779 standard, adopted both by NHTSA in the US and by Brazil (via CONTRAN Resolution No. 24/1998 and ABNT standard NBR 6066).

Next steps

Transliteration, weights and the remainder of dividing by 11

Each VIN character becomes a number before entering the calculation: digits keep their own value, and letters follow a fixed ISO 3779 table, A=1, B=2, C=3, D=4, E=5, F=6, G=7, H=8, J=1, K=2, L=3, M=4, N=5, P=7, R=9, S=2, T=3, U=4, V=5, W=6, X=7, Y=8, Z=9 (I, O and Q do not exist in a VIN). Each of the 17 positions has a weight: 8, 7, 6, 5, 4, 3, 2, 10, 0, 9, 8, 7, 6, 5, 4, 3, 2, with position 9 itself having weight 0 (it does not enter its own sum).

Multiply each value by its position's weight, sum everything, and take the remainder of dividing by 11. The check digit is that remainder, except when the remainder is 10, in which case the digit becomes the letter X. The reference VIN 1M8GDM9AXKP042788 confirms the calculation: the weighted sum of the other 16 positions is 351, whose remainder when divided by 11 is 10, which is why position 9 is X.

Verified example

Reference VIN (digit X)

Input: 1M8GDM9AXKP042788
Expected output: dígito verificador X confere

Weighted sum = 351; 351 mod 11 = 10; a remainder of 10 becomes X.

Same VIN with a tampered digit

Input: 1M8GDM9A0KP042788
Expected output: inválido, esperado X

Changing only position 9 (from X to 0) already breaks validation, the rest of the calculation stays the same.

Full tool FAQ

Is the generated VIN from a real vehicle?

No. It is a synthetic 17-character sequence computed only to satisfy the ISO 3779 check digit. The tool never queries a manufacturer, NHTSA or DENATRAN.

Why does a VIN never contain the letters I, O or Q?

How does the position-9 check digit work?

Does Brazil use the same VIN standard as the United States?

What do positions 12 to 17 mean?

Can I use the generated VIN to sell or list a vehicle?

Does a VIN with a correct check digit guarantee the vehicle has no liens?

Does the tool send the VIN to a server?

Frequently asked questions

Why does a remainder of 10 become the letter X instead of the number 10?

Because the check digit must fit a single VIN position. Since possible remainders range from 0 to 10, and 10 is not a single digit, ISO 3779 uses the letter X to represent that specific case.

Why does position 9 have weight 0 in the table?

Is this the same calculation used in the US?

Yes, it is the same international ISO 3779 standard, adopted both by NHTSA in the US and by Brazil (via CONTRAN Resolution No. 24/1998 and ABNT standard NBR 6066).